1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (C) 2009 Red Hat, Inc.
3 * Author: Michael S. Tsirkin <mst@redhat.com>
4 *
5 * virtio-net server in host kernel.
6 */
7
8#include <linux/compat.h>
9#include <linux/eventfd.h>
10#include <linux/vhost.h>
11#include <linux/virtio_net.h>
12#include <linux/miscdevice.h>
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/mutex.h>
16#include <linux/workqueue.h>
17#include <linux/file.h>
18#include <linux/slab.h>
19#include <linux/sched/clock.h>
20#include <linux/sched/signal.h>
21#include <linux/vmalloc.h>
22
23#include <linux/net.h>
24#include <linux/if_packet.h>
25#include <linux/if_arp.h>
26#include <linux/if_tun.h>
27#include <linux/if_macvlan.h>
28#include <linux/if_tap.h>
29#include <linux/if_vlan.h>
30#include <linux/skb_array.h>
31#include <linux/skbuff.h>
32
33#include <net/sock.h>
34#include <net/xdp.h>
35
36#include "vhost.h"
37
38static int experimental_zcopytx = 0;
39module_param(experimental_zcopytx, int, 0444);
40MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
41 " 1 -Enable; 0 - Disable");
42
43/* Max number of bytes transferred before requeueing the job.
44 * Using this limit prevents one virtqueue from starving others. */
45#define VHOST_NET_WEIGHT 0x80000
46
47/* Max number of packets transferred before requeueing the job.
48 * Using this limit prevents one virtqueue from starving others with small
49 * pkts.
50 */
51#define VHOST_NET_PKT_WEIGHT 256
52
53/* MAX number of TX used buffers for outstanding zerocopy */
54#define VHOST_MAX_PEND 128
55#define VHOST_GOODCOPY_LEN 256
56
57/*
58 * For transmit, used buffer len is unused; we override it to track buffer
59 * status internally; used for zerocopy tx only.
60 */
61/* Lower device DMA failed */
62#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3)
63/* Lower device DMA done */
64#define VHOST_DMA_DONE_LEN ((__force __virtio32)2)
65/* Lower device DMA in progress */
66#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1)
67/* Buffer unused */
68#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0)
69
70#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)
71
72enum {
73 VHOST_NET_FEATURES = VHOST_FEATURES |
74 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
75 (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
76 (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
77 (1ULL << VIRTIO_F_RING_RESET)
78};
79
80enum {
81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
82};
83
84enum {
85 VHOST_NET_VQ_RX = 0,
86 VHOST_NET_VQ_TX = 1,
87 VHOST_NET_VQ_MAX = 2,
88};
89
90struct vhost_net_ubuf_ref {
91 /* refcount follows semantics similar to kref:
92 * 0: object is released
93 * 1: no outstanding ubufs
94 * >1: outstanding ubufs
95 */
96 atomic_t refcount;
97 wait_queue_head_t wait;
98 struct vhost_virtqueue *vq;
99};
100
101#define VHOST_NET_BATCH 64
102struct vhost_net_buf {
103 void **queue;
104 int tail;
105 int head;
106};
107
108struct vhost_net_virtqueue {
109 struct vhost_virtqueue vq;
110 size_t vhost_hlen;
111 size_t sock_hlen;
112 /* vhost zerocopy support fields below: */
113 /* last used idx for outstanding DMA zerocopy buffers */
114 int upend_idx;
115 /* For TX, first used idx for DMA done zerocopy buffers
116 * For RX, number of batched heads
117 */
118 int done_idx;
119 /* Number of XDP frames batched */
120 int batched_xdp;
121 /* an array of userspace buffers info */
122 struct ubuf_info_msgzc *ubuf_info;
123 /* Reference counting for outstanding ubufs.
124 * Protected by vq mutex. Writers must also take device mutex. */
125 struct vhost_net_ubuf_ref *ubufs;
126 struct ptr_ring *rx_ring;
127 struct vhost_net_buf rxq;
128 /* Batched XDP buffs */
129 struct xdp_buff *xdp;
130};
131
132struct vhost_net {
133 struct vhost_dev dev;
134 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX];
135 struct vhost_poll poll[VHOST_NET_VQ_MAX];
136 /* Number of TX recently submitted.
137 * Protected by tx vq lock. */
138 unsigned tx_packets;
139 /* Number of times zerocopy TX recently failed.
140 * Protected by tx vq lock. */
141 unsigned tx_zcopy_err;
142 /* Flush in progress. Protected by tx vq lock. */
143 bool tx_flush;
144 /* Private page frag cache */
145 struct page_frag_cache pf_cache;
146};
147
148static unsigned vhost_net_zcopy_mask __read_mostly;
149
150static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq)
151{
152 if (rxq->tail != rxq->head)
153 return rxq->queue[rxq->head];
154 else
155 return NULL;
156}
157
158static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
159{
160 return rxq->tail - rxq->head;
161}
162
163static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
164{
165 return rxq->tail == rxq->head;
166}
167
168static void *vhost_net_buf_consume(struct vhost_net_buf *rxq)
169{
170 void *ret = vhost_net_buf_get_ptr(rxq);
171 ++rxq->head;
172 return ret;
173}
174
175static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
176{
177 struct vhost_net_buf *rxq = &nvq->rxq;
178
179 rxq->head = 0;
180 rxq->tail = ptr_ring_consume_batched(r: nvq->rx_ring, array: rxq->queue,
181 VHOST_NET_BATCH);
182 return rxq->tail;
183}
184
185static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
186{
187 struct vhost_net_buf *rxq = &nvq->rxq;
188
189 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
190 ptr_ring_unconsume(r: nvq->rx_ring, batch: rxq->queue + rxq->head,
191 n: vhost_net_buf_get_size(rxq),
192 destroy: tun_ptr_free);
193 rxq->head = rxq->tail = 0;
194 }
195}
196
197static int vhost_net_buf_peek_len(void *ptr)
198{
199 if (tun_is_xdp_frame(ptr)) {
200 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
201
202 return xdpf->len;
203 }
204
205 return __skb_array_len_with_tag(skb: ptr);
206}
207
208static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
209{
210 struct vhost_net_buf *rxq = &nvq->rxq;
211
212 if (!vhost_net_buf_is_empty(rxq))
213 goto out;
214
215 if (!vhost_net_buf_produce(nvq))
216 return 0;
217
218out:
219 return vhost_net_buf_peek_len(ptr: vhost_net_buf_get_ptr(rxq));
220}
221
222static void vhost_net_buf_init(struct vhost_net_buf *rxq)
223{
224 rxq->head = rxq->tail = 0;
225}
226
227static void vhost_net_enable_zcopy(int vq)
228{
229 vhost_net_zcopy_mask |= 0x1 << vq;
230}
231
232static struct vhost_net_ubuf_ref *
233vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
234{
235 struct vhost_net_ubuf_ref *ubufs;
236 /* No zero copy backend? Nothing to count. */
237 if (!zcopy)
238 return NULL;
239 ubufs = kmalloc(size: sizeof(*ubufs), GFP_KERNEL);
240 if (!ubufs)
241 return ERR_PTR(error: -ENOMEM);
242 atomic_set(v: &ubufs->refcount, i: 1);
243 init_waitqueue_head(&ubufs->wait);
244 ubufs->vq = vq;
245 return ubufs;
246}
247
248static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
249{
250 int r = atomic_sub_return(i: 1, v: &ubufs->refcount);
251 if (unlikely(!r))
252 wake_up(&ubufs->wait);
253 return r;
254}
255
256static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
257{
258 vhost_net_ubuf_put(ubufs);
259 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
260}
261
262static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
263{
264 vhost_net_ubuf_put_and_wait(ubufs);
265 kfree(objp: ubufs);
266}
267
268static void vhost_net_clear_ubuf_info(struct vhost_net *n)
269{
270 int i;
271
272 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
273 kfree(objp: n->vqs[i].ubuf_info);
274 n->vqs[i].ubuf_info = NULL;
275 }
276}
277
278static int vhost_net_set_ubuf_info(struct vhost_net *n)
279{
280 bool zcopy;
281 int i;
282
283 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
284 zcopy = vhost_net_zcopy_mask & (0x1 << i);
285 if (!zcopy)
286 continue;
287 n->vqs[i].ubuf_info =
288 kmalloc_array(UIO_MAXIOV,
289 size: sizeof(*n->vqs[i].ubuf_info),
290 GFP_KERNEL);
291 if (!n->vqs[i].ubuf_info)
292 goto err;
293 }
294 return 0;
295
296err:
297 vhost_net_clear_ubuf_info(n);
298 return -ENOMEM;
299}
300
301static void vhost_net_vq_reset(struct vhost_net *n)
302{
303 int i;
304
305 vhost_net_clear_ubuf_info(n);
306
307 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
308 n->vqs[i].done_idx = 0;
309 n->vqs[i].upend_idx = 0;
310 n->vqs[i].ubufs = NULL;
311 n->vqs[i].vhost_hlen = 0;
312 n->vqs[i].sock_hlen = 0;
313 vhost_net_buf_init(rxq: &n->vqs[i].rxq);
314 }
315
316}
317
318static void vhost_net_tx_packet(struct vhost_net *net)
319{
320 ++net->tx_packets;
321 if (net->tx_packets < 1024)
322 return;
323 net->tx_packets = 0;
324 net->tx_zcopy_err = 0;
325}
326
327static void vhost_net_tx_err(struct vhost_net *net)
328{
329 ++net->tx_zcopy_err;
330}
331
332static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
333{
334 /* TX flush waits for outstanding DMAs to be done.
335 * Don't start new DMAs.
336 */
337 return !net->tx_flush &&
338 net->tx_packets / 64 >= net->tx_zcopy_err;
339}
340
341static bool vhost_sock_zcopy(struct socket *sock)
342{
343 return unlikely(experimental_zcopytx) &&
344 sock_flag(sk: sock->sk, flag: SOCK_ZEROCOPY);
345}
346
347static bool vhost_sock_xdp(struct socket *sock)
348{
349 return sock_flag(sk: sock->sk, flag: SOCK_XDP);
350}
351
352/* In case of DMA done not in order in lower device driver for some reason.
353 * upend_idx is used to track end of used idx, done_idx is used to track head
354 * of used idx. Once lower device DMA done contiguously, we will signal KVM
355 * guest used idx.
356 */
357static void vhost_zerocopy_signal_used(struct vhost_net *net,
358 struct vhost_virtqueue *vq)
359{
360 struct vhost_net_virtqueue *nvq =
361 container_of(vq, struct vhost_net_virtqueue, vq);
362 int i, add;
363 int j = 0;
364
365 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
366 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
367 vhost_net_tx_err(net);
368 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
369 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
370 ++j;
371 } else
372 break;
373 }
374 while (j) {
375 add = min(UIO_MAXIOV - nvq->done_idx, j);
376 vhost_add_used_and_signal_n(vq->dev, vq,
377 heads: &vq->heads[nvq->done_idx], count: add);
378 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
379 j -= add;
380 }
381}
382
383static void vhost_zerocopy_callback(struct sk_buff *skb,
384 struct ubuf_info *ubuf_base, bool success)
385{
386 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
387 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
388 struct vhost_virtqueue *vq = ubufs->vq;
389 int cnt;
390
391 rcu_read_lock_bh();
392
393 /* set len to mark this desc buffers done DMA */
394 vq->heads[ubuf->desc].len = success ?
395 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
396 cnt = vhost_net_ubuf_put(ubufs);
397
398 /*
399 * Trigger polling thread if guest stopped submitting new buffers:
400 * in this case, the refcount after decrement will eventually reach 1.
401 * We also trigger polling periodically after each 16 packets
402 * (the value 16 here is more or less arbitrary, it's tuned to trigger
403 * less than 10% of times).
404 */
405 if (cnt <= 1 || !(cnt % 16))
406 vhost_poll_queue(poll: &vq->poll);
407
408 rcu_read_unlock_bh();
409}
410
411static inline unsigned long busy_clock(void)
412{
413 return local_clock() >> 10;
414}
415
416static bool vhost_can_busy_poll(unsigned long endtime)
417{
418 return likely(!need_resched() && !time_after(busy_clock(), endtime) &&
419 !signal_pending(current));
420}
421
422static void vhost_net_disable_vq(struct vhost_net *n,
423 struct vhost_virtqueue *vq)
424{
425 struct vhost_net_virtqueue *nvq =
426 container_of(vq, struct vhost_net_virtqueue, vq);
427 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
428 if (!vhost_vq_get_backend(vq))
429 return;
430 vhost_poll_stop(poll);
431}
432
433static int vhost_net_enable_vq(struct vhost_net *n,
434 struct vhost_virtqueue *vq)
435{
436 struct vhost_net_virtqueue *nvq =
437 container_of(vq, struct vhost_net_virtqueue, vq);
438 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
439 struct socket *sock;
440
441 sock = vhost_vq_get_backend(vq);
442 if (!sock)
443 return 0;
444
445 return vhost_poll_start(poll, file: sock->file);
446}
447
448static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq)
449{
450 struct vhost_virtqueue *vq = &nvq->vq;
451 struct vhost_dev *dev = vq->dev;
452
453 if (!nvq->done_idx)
454 return;
455
456 vhost_add_used_and_signal_n(dev, vq, heads: vq->heads, count: nvq->done_idx);
457 nvq->done_idx = 0;
458}
459
460static void vhost_tx_batch(struct vhost_net *net,
461 struct vhost_net_virtqueue *nvq,
462 struct socket *sock,
463 struct msghdr *msghdr)
464{
465 struct tun_msg_ctl ctl = {
466 .type = TUN_MSG_PTR,
467 .num = nvq->batched_xdp,
468 .ptr = nvq->xdp,
469 };
470 int i, err;
471
472 if (nvq->batched_xdp == 0)
473 goto signal_used;
474
475 msghdr->msg_control = &ctl;
476 msghdr->msg_controllen = sizeof(ctl);
477 err = sock->ops->sendmsg(sock, msghdr, 0);
478 if (unlikely(err < 0)) {
479 vq_err(&nvq->vq, "Fail to batch sending packets\n");
480
481 /* free pages owned by XDP; since this is an unlikely error path,
482 * keep it simple and avoid more complex bulk update for the
483 * used pages
484 */
485 for (i = 0; i < nvq->batched_xdp; ++i)
486 put_page(page: virt_to_head_page(x: nvq->xdp[i].data));
487 nvq->batched_xdp = 0;
488 nvq->done_idx = 0;
489 return;
490 }
491
492signal_used:
493 vhost_net_signal_used(nvq);
494 nvq->batched_xdp = 0;
495}
496
497static int sock_has_rx_data(struct socket *sock)
498{
499 if (unlikely(!sock))
500 return 0;
501
502 if (sock->ops->peek_len)
503 return sock->ops->peek_len(sock);
504
505 return skb_queue_empty(list: &sock->sk->sk_receive_queue);
506}
507
508static void vhost_net_busy_poll_try_queue(struct vhost_net *net,
509 struct vhost_virtqueue *vq)
510{
511 if (!vhost_vq_avail_empty(&net->dev, vq)) {
512 vhost_poll_queue(poll: &vq->poll);
513 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
514 vhost_disable_notify(&net->dev, vq);
515 vhost_poll_queue(poll: &vq->poll);
516 }
517}
518
519static void vhost_net_busy_poll(struct vhost_net *net,
520 struct vhost_virtqueue *rvq,
521 struct vhost_virtqueue *tvq,
522 bool *busyloop_intr,
523 bool poll_rx)
524{
525 unsigned long busyloop_timeout;
526 unsigned long endtime;
527 struct socket *sock;
528 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq;
529
530 /* Try to hold the vq mutex of the paired virtqueue. We can't
531 * use mutex_lock() here since we could not guarantee a
532 * consistenet lock ordering.
533 */
534 if (!mutex_trylock(lock: &vq->mutex))
535 return;
536
537 vhost_disable_notify(&net->dev, vq);
538 sock = vhost_vq_get_backend(vq: rvq);
539
540 busyloop_timeout = poll_rx ? rvq->busyloop_timeout:
541 tvq->busyloop_timeout;
542
543 preempt_disable();
544 endtime = busy_clock() + busyloop_timeout;
545
546 while (vhost_can_busy_poll(endtime)) {
547 if (vhost_vq_has_work(vq)) {
548 *busyloop_intr = true;
549 break;
550 }
551
552 if ((sock_has_rx_data(sock) &&
553 !vhost_vq_avail_empty(&net->dev, rvq)) ||
554 !vhost_vq_avail_empty(&net->dev, tvq))
555 break;
556
557 cpu_relax();
558 }
559
560 preempt_enable();
561
562 if (poll_rx || sock_has_rx_data(sock))
563 vhost_net_busy_poll_try_queue(net, vq);
564 else if (!poll_rx) /* On tx here, sock has no rx data. */
565 vhost_enable_notify(&net->dev, rvq);
566
567 mutex_unlock(lock: &vq->mutex);
568}
569
570static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
571 struct vhost_net_virtqueue *tnvq,
572 unsigned int *out_num, unsigned int *in_num,
573 struct msghdr *msghdr, bool *busyloop_intr)
574{
575 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
576 struct vhost_virtqueue *rvq = &rnvq->vq;
577 struct vhost_virtqueue *tvq = &tnvq->vq;
578
579 int r = vhost_get_vq_desc(tvq, iov: tvq->iov, ARRAY_SIZE(tvq->iov),
580 out_num, in_num, NULL, NULL);
581
582 if (r == tvq->num && tvq->busyloop_timeout) {
583 /* Flush batched packets first */
584 if (!vhost_sock_zcopy(sock: vhost_vq_get_backend(vq: tvq)))
585 vhost_tx_batch(net, nvq: tnvq,
586 sock: vhost_vq_get_backend(vq: tvq),
587 msghdr);
588
589 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, poll_rx: false);
590
591 r = vhost_get_vq_desc(tvq, iov: tvq->iov, ARRAY_SIZE(tvq->iov),
592 out_num, in_num, NULL, NULL);
593 }
594
595 return r;
596}
597
598static bool vhost_exceeds_maxpend(struct vhost_net *net)
599{
600 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
601 struct vhost_virtqueue *vq = &nvq->vq;
602
603 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV >
604 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2);
605}
606
607static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
608 size_t hdr_size, int out)
609{
610 /* Skip header. TODO: support TSO. */
611 size_t len = iov_length(iov: vq->iov, nr_segs: out);
612
613 iov_iter_init(i: iter, ITER_SOURCE, iov: vq->iov, nr_segs: out, count: len);
614 iov_iter_advance(i: iter, bytes: hdr_size);
615
616 return iov_iter_count(i: iter);
617}
618
619static int get_tx_bufs(struct vhost_net *net,
620 struct vhost_net_virtqueue *nvq,
621 struct msghdr *msg,
622 unsigned int *out, unsigned int *in,
623 size_t *len, bool *busyloop_intr)
624{
625 struct vhost_virtqueue *vq = &nvq->vq;
626 int ret;
627
628 ret = vhost_net_tx_get_vq_desc(net, tnvq: nvq, out_num: out, in_num: in, msghdr: msg, busyloop_intr);
629
630 if (ret < 0 || ret == vq->num)
631 return ret;
632
633 if (*in) {
634 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
635 *out, *in);
636 return -EFAULT;
637 }
638
639 /* Sanity check */
640 *len = init_iov_iter(vq, iter: &msg->msg_iter, hdr_size: nvq->vhost_hlen, out: *out);
641 if (*len == 0) {
642 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
643 *len, nvq->vhost_hlen);
644 return -EFAULT;
645 }
646
647 return ret;
648}
649
650static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len)
651{
652 return total_len < VHOST_NET_WEIGHT &&
653 !vhost_vq_avail_empty(vq->dev, vq);
654}
655
656#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
657
658static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
659 struct iov_iter *from)
660{
661 struct vhost_virtqueue *vq = &nvq->vq;
662 struct vhost_net *net = container_of(vq->dev, struct vhost_net,
663 dev);
664 struct socket *sock = vhost_vq_get_backend(vq);
665 struct virtio_net_hdr *gso;
666 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];
667 struct tun_xdp_hdr *hdr;
668 size_t len = iov_iter_count(i: from);
669 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0;
670 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
671 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen);
672 int sock_hlen = nvq->sock_hlen;
673 void *buf;
674 int copied;
675 int ret;
676
677 if (unlikely(len < nvq->sock_hlen))
678 return -EFAULT;
679
680 if (SKB_DATA_ALIGN(len + pad) +
681 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
682 return -ENOSPC;
683
684 buflen += SKB_DATA_ALIGN(len + pad);
685 buf = page_frag_alloc_align(nc: &net->pf_cache, fragsz: buflen, GFP_KERNEL,
686 SMP_CACHE_BYTES);
687 if (unlikely(!buf))
688 return -ENOMEM;
689
690 copied = copy_from_iter(addr: buf + offsetof(struct tun_xdp_hdr, gso),
691 bytes: sock_hlen, i: from);
692 if (copied != sock_hlen) {
693 ret = -EFAULT;
694 goto err;
695 }
696
697 hdr = buf;
698 gso = &hdr->gso;
699
700 if (!sock_hlen)
701 memset(buf, 0, pad);
702
703 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
704 vhost16_to_cpu(vq, val: gso->csum_start) +
705 vhost16_to_cpu(vq, val: gso->csum_offset) + 2 >
706 vhost16_to_cpu(vq, val: gso->hdr_len)) {
707 gso->hdr_len = cpu_to_vhost16(vq,
708 val: vhost16_to_cpu(vq, val: gso->csum_start) +
709 vhost16_to_cpu(vq, val: gso->csum_offset) + 2);
710
711 if (vhost16_to_cpu(vq, val: gso->hdr_len) > len) {
712 ret = -EINVAL;
713 goto err;
714 }
715 }
716
717 len -= sock_hlen;
718 copied = copy_from_iter(addr: buf + pad, bytes: len, i: from);
719 if (copied != len) {
720 ret = -EFAULT;
721 goto err;
722 }
723
724 xdp_init_buff(xdp, frame_sz: buflen, NULL);
725 xdp_prepare_buff(xdp, hard_start: buf, headroom: pad, data_len: len, meta_valid: true);
726 hdr->buflen = buflen;
727
728 ++nvq->batched_xdp;
729
730 return 0;
731
732err:
733 page_frag_free(addr: buf);
734 return ret;
735}
736
737static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
738{
739 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
740 struct vhost_virtqueue *vq = &nvq->vq;
741 unsigned out, in;
742 int head;
743 struct msghdr msg = {
744 .msg_name = NULL,
745 .msg_namelen = 0,
746 .msg_control = NULL,
747 .msg_controllen = 0,
748 .msg_flags = MSG_DONTWAIT,
749 };
750 size_t len, total_len = 0;
751 int err;
752 int sent_pkts = 0;
753 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
754
755 do {
756 bool busyloop_intr = false;
757
758 if (nvq->done_idx == VHOST_NET_BATCH)
759 vhost_tx_batch(net, nvq, sock, msghdr: &msg);
760
761 head = get_tx_bufs(net, nvq, msg: &msg, out: &out, in: &in, len: &len,
762 busyloop_intr: &busyloop_intr);
763 /* On error, stop handling until the next kick. */
764 if (unlikely(head < 0))
765 break;
766 /* Nothing new? Wait for eventfd to tell us they refilled. */
767 if (head == vq->num) {
768 if (unlikely(busyloop_intr)) {
769 vhost_poll_queue(poll: &vq->poll);
770 } else if (unlikely(vhost_enable_notify(&net->dev,
771 vq))) {
772 vhost_disable_notify(&net->dev, vq);
773 continue;
774 }
775 break;
776 }
777
778 total_len += len;
779
780 /* For simplicity, TX batching is only enabled if
781 * sndbuf is unlimited.
782 */
783 if (sock_can_batch) {
784 err = vhost_net_build_xdp(nvq, from: &msg.msg_iter);
785 if (!err) {
786 goto done;
787 } else if (unlikely(err != -ENOSPC)) {
788 vhost_tx_batch(net, nvq, sock, msghdr: &msg);
789 vhost_discard_vq_desc(vq, n: 1);
790 vhost_net_enable_vq(n: net, vq);
791 break;
792 }
793
794 /* We can't build XDP buff, go for single
795 * packet path but let's flush batched
796 * packets.
797 */
798 vhost_tx_batch(net, nvq, sock, msghdr: &msg);
799 msg.msg_control = NULL;
800 } else {
801 if (tx_can_batch(vq, total_len))
802 msg.msg_flags |= MSG_MORE;
803 else
804 msg.msg_flags &= ~MSG_MORE;
805 }
806
807 err = sock->ops->sendmsg(sock, &msg, len);
808 if (unlikely(err < 0)) {
809 if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) {
810 vhost_discard_vq_desc(vq, n: 1);
811 vhost_net_enable_vq(n: net, vq);
812 break;
813 }
814 pr_debug("Fail to send packet: err %d", err);
815 } else if (unlikely(err != len))
816 pr_debug("Truncated TX packet: len %d != %zd\n",
817 err, len);
818done:
819 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, val: head);
820 vq->heads[nvq->done_idx].len = 0;
821 ++nvq->done_idx;
822 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
823
824 vhost_tx_batch(net, nvq, sock, msghdr: &msg);
825}
826
827static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
828{
829 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
830 struct vhost_virtqueue *vq = &nvq->vq;
831 unsigned out, in;
832 int head;
833 struct msghdr msg = {
834 .msg_name = NULL,
835 .msg_namelen = 0,
836 .msg_control = NULL,
837 .msg_controllen = 0,
838 .msg_flags = MSG_DONTWAIT,
839 };
840 struct tun_msg_ctl ctl;
841 size_t len, total_len = 0;
842 int err;
843 struct vhost_net_ubuf_ref *ubufs;
844 struct ubuf_info_msgzc *ubuf;
845 bool zcopy_used;
846 int sent_pkts = 0;
847
848 do {
849 bool busyloop_intr;
850
851 /* Release DMAs done buffers first */
852 vhost_zerocopy_signal_used(net, vq);
853
854 busyloop_intr = false;
855 head = get_tx_bufs(net, nvq, msg: &msg, out: &out, in: &in, len: &len,
856 busyloop_intr: &busyloop_intr);
857 /* On error, stop handling until the next kick. */
858 if (unlikely(head < 0))
859 break;
860 /* Nothing new? Wait for eventfd to tell us they refilled. */
861 if (head == vq->num) {
862 if (unlikely(busyloop_intr)) {
863 vhost_poll_queue(poll: &vq->poll);
864 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
865 vhost_disable_notify(&net->dev, vq);
866 continue;
867 }
868 break;
869 }
870
871 zcopy_used = len >= VHOST_GOODCOPY_LEN
872 && !vhost_exceeds_maxpend(net)
873 && vhost_net_tx_select_zcopy(net);
874
875 /* use msg_control to pass vhost zerocopy ubuf info to skb */
876 if (zcopy_used) {
877 ubuf = nvq->ubuf_info + nvq->upend_idx;
878 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, val: head);
879 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
880 ubuf->ctx = nvq->ubufs;
881 ubuf->desc = nvq->upend_idx;
882 ubuf->ubuf.callback = vhost_zerocopy_callback;
883 ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG;
884 refcount_set(r: &ubuf->ubuf.refcnt, n: 1);
885 msg.msg_control = &ctl;
886 ctl.type = TUN_MSG_UBUF;
887 ctl.ptr = &ubuf->ubuf;
888 msg.msg_controllen = sizeof(ctl);
889 ubufs = nvq->ubufs;
890 atomic_inc(v: &ubufs->refcount);
891 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
892 } else {
893 msg.msg_control = NULL;
894 ubufs = NULL;
895 }
896 total_len += len;
897 if (tx_can_batch(vq, total_len) &&
898 likely(!vhost_exceeds_maxpend(net))) {
899 msg.msg_flags |= MSG_MORE;
900 } else {
901 msg.msg_flags &= ~MSG_MORE;
902 }
903
904 err = sock->ops->sendmsg(sock, &msg, len);
905 if (unlikely(err < 0)) {
906 bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS;
907
908 if (zcopy_used) {
909 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS)
910 vhost_net_ubuf_put(ubufs);
911 if (retry)
912 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
913 % UIO_MAXIOV;
914 else
915 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
916 }
917 if (retry) {
918 vhost_discard_vq_desc(vq, n: 1);
919 vhost_net_enable_vq(n: net, vq);
920 break;
921 }
922 pr_debug("Fail to send packet: err %d", err);
923 } else if (unlikely(err != len))
924 pr_debug("Truncated TX packet: "
925 " len %d != %zd\n", err, len);
926 if (!zcopy_used)
927 vhost_add_used_and_signal(&net->dev, vq, id: head, len: 0);
928 else
929 vhost_zerocopy_signal_used(net, vq);
930 vhost_net_tx_packet(net);
931 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
932}
933
934/* Expects to be always run from workqueue - which acts as
935 * read-size critical section for our kind of RCU. */
936static void handle_tx(struct vhost_net *net)
937{
938 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
939 struct vhost_virtqueue *vq = &nvq->vq;
940 struct socket *sock;
941
942 mutex_lock_nested(lock: &vq->mutex, subclass: VHOST_NET_VQ_TX);
943 sock = vhost_vq_get_backend(vq);
944 if (!sock)
945 goto out;
946
947 if (!vq_meta_prefetch(vq))
948 goto out;
949
950 vhost_disable_notify(&net->dev, vq);
951 vhost_net_disable_vq(n: net, vq);
952
953 if (vhost_sock_zcopy(sock))
954 handle_tx_zerocopy(net, sock);
955 else
956 handle_tx_copy(net, sock);
957
958out:
959 mutex_unlock(lock: &vq->mutex);
960}
961
962static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
963{
964 struct sk_buff *head;
965 int len = 0;
966 unsigned long flags;
967
968 if (rvq->rx_ring)
969 return vhost_net_buf_peek(nvq: rvq);
970
971 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
972 head = skb_peek(list_: &sk->sk_receive_queue);
973 if (likely(head)) {
974 len = head->len;
975 if (skb_vlan_tag_present(head))
976 len += VLAN_HLEN;
977 }
978
979 spin_unlock_irqrestore(lock: &sk->sk_receive_queue.lock, flags);
980 return len;
981}
982
983static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
984 bool *busyloop_intr)
985{
986 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
987 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
988 struct vhost_virtqueue *rvq = &rnvq->vq;
989 struct vhost_virtqueue *tvq = &tnvq->vq;
990 int len = peek_head_len(rvq: rnvq, sk);
991
992 if (!len && rvq->busyloop_timeout) {
993 /* Flush batched heads first */
994 vhost_net_signal_used(nvq: rnvq);
995 /* Both tx vq and rx socket were polled here */
996 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, poll_rx: true);
997
998 len = peek_head_len(rvq: rnvq, sk);
999 }
1000
1001 return len;
1002}
1003
1004/* This is a multi-buffer version of vhost_get_desc, that works if
1005 * vq has read descriptors only.
1006 * @vq - the relevant virtqueue
1007 * @datalen - data length we'll be reading
1008 * @iovcount - returned count of io vectors we fill
1009 * @log - vhost log
1010 * @log_num - log offset
1011 * @quota - headcount quota, 1 for big buffer
1012 * returns number of buffer heads allocated, negative on error
1013 */
1014static int get_rx_bufs(struct vhost_virtqueue *vq,
1015 struct vring_used_elem *heads,
1016 int datalen,
1017 unsigned *iovcount,
1018 struct vhost_log *log,
1019 unsigned *log_num,
1020 unsigned int quota)
1021{
1022 unsigned int out, in;
1023 int seg = 0;
1024 int headcount = 0;
1025 unsigned d;
1026 int r, nlogs = 0;
1027 /* len is always initialized before use since we are always called with
1028 * datalen > 0.
1029 */
1030 u32 len;
1031
1032 while (datalen > 0 && headcount < quota) {
1033 if (unlikely(seg >= UIO_MAXIOV)) {
1034 r = -ENOBUFS;
1035 goto err;
1036 }
1037 r = vhost_get_vq_desc(vq, iov: vq->iov + seg,
1038 ARRAY_SIZE(vq->iov) - seg, out_num: &out,
1039 in_num: &in, log, log_num);
1040 if (unlikely(r < 0))
1041 goto err;
1042
1043 d = r;
1044 if (d == vq->num) {
1045 r = 0;
1046 goto err;
1047 }
1048 if (unlikely(out || in <= 0)) {
1049 vq_err(vq, "unexpected descriptor format for RX: "
1050 "out %d, in %d\n", out, in);
1051 r = -EINVAL;
1052 goto err;
1053 }
1054 if (unlikely(log)) {
1055 nlogs += *log_num;
1056 log += *log_num;
1057 }
1058 heads[headcount].id = cpu_to_vhost32(vq, val: d);
1059 len = iov_length(iov: vq->iov + seg, nr_segs: in);
1060 heads[headcount].len = cpu_to_vhost32(vq, val: len);
1061 datalen -= len;
1062 ++headcount;
1063 seg += in;
1064 }
1065 heads[headcount - 1].len = cpu_to_vhost32(vq, val: len + datalen);
1066 *iovcount = seg;
1067 if (unlikely(log))
1068 *log_num = nlogs;
1069
1070 /* Detect overrun */
1071 if (unlikely(datalen > 0)) {
1072 r = UIO_MAXIOV + 1;
1073 goto err;
1074 }
1075 return headcount;
1076err:
1077 vhost_discard_vq_desc(vq, n: headcount);
1078 return r;
1079}
1080
1081/* Expects to be always run from workqueue - which acts as
1082 * read-size critical section for our kind of RCU. */
1083static void handle_rx(struct vhost_net *net)
1084{
1085 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
1086 struct vhost_virtqueue *vq = &nvq->vq;
1087 unsigned in, log;
1088 struct vhost_log *vq_log;
1089 struct msghdr msg = {
1090 .msg_name = NULL,
1091 .msg_namelen = 0,
1092 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
1093 .msg_controllen = 0,
1094 .msg_flags = MSG_DONTWAIT,
1095 };
1096 struct virtio_net_hdr hdr = {
1097 .flags = 0,
1098 .gso_type = VIRTIO_NET_HDR_GSO_NONE
1099 };
1100 size_t total_len = 0;
1101 int err, mergeable;
1102 s16 headcount;
1103 size_t vhost_hlen, sock_hlen;
1104 size_t vhost_len, sock_len;
1105 bool busyloop_intr = false;
1106 struct socket *sock;
1107 struct iov_iter fixup;
1108 __virtio16 num_buffers;
1109 int recv_pkts = 0;
1110
1111 mutex_lock_nested(lock: &vq->mutex, subclass: VHOST_NET_VQ_RX);
1112 sock = vhost_vq_get_backend(vq);
1113 if (!sock)
1114 goto out;
1115
1116 if (!vq_meta_prefetch(vq))
1117 goto out;
1118
1119 vhost_disable_notify(&net->dev, vq);
1120 vhost_net_disable_vq(n: net, vq);
1121
1122 vhost_hlen = nvq->vhost_hlen;
1123 sock_hlen = nvq->sock_hlen;
1124
1125 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
1126 vq->log : NULL;
1127 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
1128
1129 do {
1130 sock_len = vhost_net_rx_peek_head_len(net, sk: sock->sk,
1131 busyloop_intr: &busyloop_intr);
1132 if (!sock_len)
1133 break;
1134 sock_len += sock_hlen;
1135 vhost_len = sock_len + vhost_hlen;
1136 headcount = get_rx_bufs(vq, heads: vq->heads + nvq->done_idx,
1137 datalen: vhost_len, iovcount: &in, log: vq_log, log_num: &log,
1138 likely(mergeable) ? UIO_MAXIOV : 1);
1139 /* On error, stop handling until the next kick. */
1140 if (unlikely(headcount < 0))
1141 goto out;
1142 /* OK, now we need to know about added descriptors. */
1143 if (!headcount) {
1144 if (unlikely(busyloop_intr)) {
1145 vhost_poll_queue(poll: &vq->poll);
1146 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
1147 /* They have slipped one in as we were
1148 * doing that: check again. */
1149 vhost_disable_notify(&net->dev, vq);
1150 continue;
1151 }
1152 /* Nothing new? Wait for eventfd to tell us
1153 * they refilled. */
1154 goto out;
1155 }
1156 busyloop_intr = false;
1157 if (nvq->rx_ring)
1158 msg.msg_control = vhost_net_buf_consume(rxq: &nvq->rxq);
1159 /* On overrun, truncate and discard */
1160 if (unlikely(headcount > UIO_MAXIOV)) {
1161 iov_iter_init(i: &msg.msg_iter, ITER_DEST, iov: vq->iov, nr_segs: 1, count: 1);
1162 err = sock->ops->recvmsg(sock, &msg,
1163 1, MSG_DONTWAIT | MSG_TRUNC);
1164 pr_debug("Discarded rx packet: len %zd\n", sock_len);
1165 continue;
1166 }
1167 /* We don't need to be notified again. */
1168 iov_iter_init(i: &msg.msg_iter, ITER_DEST, iov: vq->iov, nr_segs: in, count: vhost_len);
1169 fixup = msg.msg_iter;
1170 if (unlikely((vhost_hlen))) {
1171 /* We will supply the header ourselves
1172 * TODO: support TSO.
1173 */
1174 iov_iter_advance(i: &msg.msg_iter, bytes: vhost_hlen);
1175 }
1176 err = sock->ops->recvmsg(sock, &msg,
1177 sock_len, MSG_DONTWAIT | MSG_TRUNC);
1178 /* Userspace might have consumed the packet meanwhile:
1179 * it's not supposed to do this usually, but might be hard
1180 * to prevent. Discard data we got (if any) and keep going. */
1181 if (unlikely(err != sock_len)) {
1182 pr_debug("Discarded rx packet: "
1183 " len %d, expected %zd\n", err, sock_len);
1184 vhost_discard_vq_desc(vq, n: headcount);
1185 continue;
1186 }
1187 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
1188 if (unlikely(vhost_hlen)) {
1189 if (copy_to_iter(addr: &hdr, bytes: sizeof(hdr),
1190 i: &fixup) != sizeof(hdr)) {
1191 vq_err(vq, "Unable to write vnet_hdr "
1192 "at addr %p\n", vq->iov->iov_base);
1193 goto out;
1194 }
1195 } else {
1196 /* Header came from socket; we'll need to patch
1197 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
1198 */
1199 iov_iter_advance(i: &fixup, bytes: sizeof(hdr));
1200 }
1201 /* TODO: Should check and handle checksum. */
1202
1203 num_buffers = cpu_to_vhost16(vq, val: headcount);
1204 if (likely(mergeable) &&
1205 copy_to_iter(addr: &num_buffers, bytes: sizeof num_buffers,
1206 i: &fixup) != sizeof num_buffers) {
1207 vq_err(vq, "Failed num_buffers write");
1208 vhost_discard_vq_desc(vq, n: headcount);
1209 goto out;
1210 }
1211 nvq->done_idx += headcount;
1212 if (nvq->done_idx > VHOST_NET_BATCH)
1213 vhost_net_signal_used(nvq);
1214 if (unlikely(vq_log))
1215 vhost_log_write(vq, log: vq_log, log_num: log, len: vhost_len,
1216 iov: vq->iov, count: in);
1217 total_len += vhost_len;
1218 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len)));
1219
1220 if (unlikely(busyloop_intr))
1221 vhost_poll_queue(poll: &vq->poll);
1222 else if (!sock_len)
1223 vhost_net_enable_vq(n: net, vq);
1224out:
1225 vhost_net_signal_used(nvq);
1226 mutex_unlock(lock: &vq->mutex);
1227}
1228
1229static void handle_tx_kick(struct vhost_work *work)
1230{
1231 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1232 poll.work);
1233 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1234
1235 handle_tx(net);
1236}
1237
1238static void handle_rx_kick(struct vhost_work *work)
1239{
1240 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1241 poll.work);
1242 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1243
1244 handle_rx(net);
1245}
1246
1247static void handle_tx_net(struct vhost_work *work)
1248{
1249 struct vhost_net *net = container_of(work, struct vhost_net,
1250 poll[VHOST_NET_VQ_TX].work);
1251 handle_tx(net);
1252}
1253
1254static void handle_rx_net(struct vhost_work *work)
1255{
1256 struct vhost_net *net = container_of(work, struct vhost_net,
1257 poll[VHOST_NET_VQ_RX].work);
1258 handle_rx(net);
1259}
1260
1261static int vhost_net_open(struct inode *inode, struct file *f)
1262{
1263 struct vhost_net *n;
1264 struct vhost_dev *dev;
1265 struct vhost_virtqueue **vqs;
1266 void **queue;
1267 struct xdp_buff *xdp;
1268 int i;
1269
1270 n = kvmalloc(size: sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1271 if (!n)
1272 return -ENOMEM;
1273 vqs = kmalloc_array(n: VHOST_NET_VQ_MAX, size: sizeof(*vqs), GFP_KERNEL);
1274 if (!vqs) {
1275 kvfree(addr: n);
1276 return -ENOMEM;
1277 }
1278
1279 queue = kmalloc_array(VHOST_NET_BATCH, size: sizeof(void *),
1280 GFP_KERNEL);
1281 if (!queue) {
1282 kfree(objp: vqs);
1283 kvfree(addr: n);
1284 return -ENOMEM;
1285 }
1286 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
1287
1288 xdp = kmalloc_array(VHOST_NET_BATCH, size: sizeof(*xdp), GFP_KERNEL);
1289 if (!xdp) {
1290 kfree(objp: vqs);
1291 kvfree(addr: n);
1292 kfree(objp: queue);
1293 return -ENOMEM;
1294 }
1295 n->vqs[VHOST_NET_VQ_TX].xdp = xdp;
1296
1297 dev = &n->dev;
1298 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
1299 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
1300 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
1301 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
1302 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
1303 n->vqs[i].ubufs = NULL;
1304 n->vqs[i].ubuf_info = NULL;
1305 n->vqs[i].upend_idx = 0;
1306 n->vqs[i].done_idx = 0;
1307 n->vqs[i].batched_xdp = 0;
1308 n->vqs[i].vhost_hlen = 0;
1309 n->vqs[i].sock_hlen = 0;
1310 n->vqs[i].rx_ring = NULL;
1311 vhost_net_buf_init(rxq: &n->vqs[i].rxq);
1312 }
1313 vhost_dev_init(dev, vqs, nvqs: VHOST_NET_VQ_MAX,
1314 UIO_MAXIOV + VHOST_NET_BATCH,
1315 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, use_worker: true,
1316 NULL);
1317
1318 vhost_poll_init(poll: n->poll + VHOST_NET_VQ_TX, fn: handle_tx_net, EPOLLOUT, dev,
1319 vq: vqs[VHOST_NET_VQ_TX]);
1320 vhost_poll_init(poll: n->poll + VHOST_NET_VQ_RX, fn: handle_rx_net, EPOLLIN, dev,
1321 vq: vqs[VHOST_NET_VQ_RX]);
1322
1323 f->private_data = n;
1324 n->pf_cache.va = NULL;
1325
1326 return 0;
1327}
1328
1329static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1330 struct vhost_virtqueue *vq)
1331{
1332 struct socket *sock;
1333 struct vhost_net_virtqueue *nvq =
1334 container_of(vq, struct vhost_net_virtqueue, vq);
1335
1336 mutex_lock(&vq->mutex);
1337 sock = vhost_vq_get_backend(vq);
1338 vhost_net_disable_vq(n, vq);
1339 vhost_vq_set_backend(vq, NULL);
1340 vhost_net_buf_unproduce(nvq);
1341 nvq->rx_ring = NULL;
1342 mutex_unlock(lock: &vq->mutex);
1343 return sock;
1344}
1345
1346static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1347 struct socket **rx_sock)
1348{
1349 *tx_sock = vhost_net_stop_vq(n, vq: &n->vqs[VHOST_NET_VQ_TX].vq);
1350 *rx_sock = vhost_net_stop_vq(n, vq: &n->vqs[VHOST_NET_VQ_RX].vq);
1351}
1352
1353static void vhost_net_flush(struct vhost_net *n)
1354{
1355 vhost_dev_flush(dev: &n->dev);
1356 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1357 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1358 n->tx_flush = true;
1359 mutex_unlock(lock: &n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1360 /* Wait for all lower device DMAs done. */
1361 vhost_net_ubuf_put_and_wait(ubufs: n->vqs[VHOST_NET_VQ_TX].ubufs);
1362 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1363 n->tx_flush = false;
1364 atomic_set(v: &n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, i: 1);
1365 mutex_unlock(lock: &n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1366 }
1367}
1368
1369static int vhost_net_release(struct inode *inode, struct file *f)
1370{
1371 struct vhost_net *n = f->private_data;
1372 struct socket *tx_sock;
1373 struct socket *rx_sock;
1374
1375 vhost_net_stop(n, tx_sock: &tx_sock, rx_sock: &rx_sock);
1376 vhost_net_flush(n);
1377 vhost_dev_stop(&n->dev);
1378 vhost_dev_cleanup(&n->dev);
1379 vhost_net_vq_reset(n);
1380 if (tx_sock)
1381 sockfd_put(tx_sock);
1382 if (rx_sock)
1383 sockfd_put(rx_sock);
1384 /* Make sure no callbacks are outstanding */
1385 synchronize_rcu();
1386 /* We do an extra flush before freeing memory,
1387 * since jobs can re-queue themselves. */
1388 vhost_net_flush(n);
1389 kfree(objp: n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1390 kfree(objp: n->vqs[VHOST_NET_VQ_TX].xdp);
1391 kfree(objp: n->dev.vqs);
1392 page_frag_cache_drain(nc: &n->pf_cache);
1393 kvfree(addr: n);
1394 return 0;
1395}
1396
1397static struct socket *get_raw_socket(int fd)
1398{
1399 int r;
1400 struct socket *sock = sockfd_lookup(fd, err: &r);
1401
1402 if (!sock)
1403 return ERR_PTR(error: -ENOTSOCK);
1404
1405 /* Parameter checking */
1406 if (sock->sk->sk_type != SOCK_RAW) {
1407 r = -ESOCKTNOSUPPORT;
1408 goto err;
1409 }
1410
1411 if (sock->sk->sk_family != AF_PACKET) {
1412 r = -EPFNOSUPPORT;
1413 goto err;
1414 }
1415 return sock;
1416err:
1417 sockfd_put(sock);
1418 return ERR_PTR(error: r);
1419}
1420
1421static struct ptr_ring *get_tap_ptr_ring(struct file *file)
1422{
1423 struct ptr_ring *ring;
1424 ring = tun_get_tx_ring(file);
1425 if (!IS_ERR(ptr: ring))
1426 goto out;
1427 ring = tap_get_ptr_ring(file);
1428 if (!IS_ERR(ptr: ring))
1429 goto out;
1430 ring = NULL;
1431out:
1432 return ring;
1433}
1434
1435static struct socket *get_tap_socket(int fd)
1436{
1437 struct file *file = fget(fd);
1438 struct socket *sock;
1439
1440 if (!file)
1441 return ERR_PTR(error: -EBADF);
1442 sock = tun_get_socket(file);
1443 if (!IS_ERR(ptr: sock))
1444 return sock;
1445 sock = tap_get_socket(file);
1446 if (IS_ERR(ptr: sock))
1447 fput(file);
1448 return sock;
1449}
1450
1451static struct socket *get_socket(int fd)
1452{
1453 struct socket *sock;
1454
1455 /* special case to disable backend */
1456 if (fd == -1)
1457 return NULL;
1458 sock = get_raw_socket(fd);
1459 if (!IS_ERR(ptr: sock))
1460 return sock;
1461 sock = get_tap_socket(fd);
1462 if (!IS_ERR(ptr: sock))
1463 return sock;
1464 return ERR_PTR(error: -ENOTSOCK);
1465}
1466
1467static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1468{
1469 struct socket *sock, *oldsock;
1470 struct vhost_virtqueue *vq;
1471 struct vhost_net_virtqueue *nvq;
1472 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1473 int r;
1474
1475 mutex_lock(&n->dev.mutex);
1476 r = vhost_dev_check_owner(&n->dev);
1477 if (r)
1478 goto err;
1479
1480 if (index >= VHOST_NET_VQ_MAX) {
1481 r = -ENOBUFS;
1482 goto err;
1483 }
1484 vq = &n->vqs[index].vq;
1485 nvq = &n->vqs[index];
1486 mutex_lock(&vq->mutex);
1487
1488 if (fd == -1)
1489 vhost_clear_msg(dev: &n->dev);
1490
1491 /* Verify that ring has been setup correctly. */
1492 if (!vhost_vq_access_ok(vq)) {
1493 r = -EFAULT;
1494 goto err_vq;
1495 }
1496 sock = get_socket(fd);
1497 if (IS_ERR(ptr: sock)) {
1498 r = PTR_ERR(ptr: sock);
1499 goto err_vq;
1500 }
1501
1502 /* start polling new socket */
1503 oldsock = vhost_vq_get_backend(vq);
1504 if (sock != oldsock) {
1505 ubufs = vhost_net_ubuf_alloc(vq,
1506 zcopy: sock && vhost_sock_zcopy(sock));
1507 if (IS_ERR(ptr: ubufs)) {
1508 r = PTR_ERR(ptr: ubufs);
1509 goto err_ubufs;
1510 }
1511
1512 vhost_net_disable_vq(n, vq);
1513 vhost_vq_set_backend(vq, private_data: sock);
1514 vhost_net_buf_unproduce(nvq);
1515 r = vhost_vq_init_access(vq);
1516 if (r)
1517 goto err_used;
1518 r = vhost_net_enable_vq(n, vq);
1519 if (r)
1520 goto err_used;
1521 if (index == VHOST_NET_VQ_RX) {
1522 if (sock)
1523 nvq->rx_ring = get_tap_ptr_ring(file: sock->file);
1524 else
1525 nvq->rx_ring = NULL;
1526 }
1527
1528 oldubufs = nvq->ubufs;
1529 nvq->ubufs = ubufs;
1530
1531 n->tx_packets = 0;
1532 n->tx_zcopy_err = 0;
1533 n->tx_flush = false;
1534 }
1535
1536 mutex_unlock(lock: &vq->mutex);
1537
1538 if (oldubufs) {
1539 vhost_net_ubuf_put_wait_and_free(ubufs: oldubufs);
1540 mutex_lock(&vq->mutex);
1541 vhost_zerocopy_signal_used(net: n, vq);
1542 mutex_unlock(lock: &vq->mutex);
1543 }
1544
1545 if (oldsock) {
1546 vhost_dev_flush(dev: &n->dev);
1547 sockfd_put(oldsock);
1548 }
1549
1550 mutex_unlock(lock: &n->dev.mutex);
1551 return 0;
1552
1553err_used:
1554 vhost_vq_set_backend(vq, private_data: oldsock);
1555 vhost_net_enable_vq(n, vq);
1556 if (ubufs)
1557 vhost_net_ubuf_put_wait_and_free(ubufs);
1558err_ubufs:
1559 if (sock)
1560 sockfd_put(sock);
1561err_vq:
1562 mutex_unlock(lock: &vq->mutex);
1563err:
1564 mutex_unlock(lock: &n->dev.mutex);
1565 return r;
1566}
1567
1568static long vhost_net_reset_owner(struct vhost_net *n)
1569{
1570 struct socket *tx_sock = NULL;
1571 struct socket *rx_sock = NULL;
1572 long err;
1573 struct vhost_iotlb *umem;
1574
1575 mutex_lock(&n->dev.mutex);
1576 err = vhost_dev_check_owner(&n->dev);
1577 if (err)
1578 goto done;
1579 umem = vhost_dev_reset_owner_prepare();
1580 if (!umem) {
1581 err = -ENOMEM;
1582 goto done;
1583 }
1584 vhost_net_stop(n, tx_sock: &tx_sock, rx_sock: &rx_sock);
1585 vhost_net_flush(n);
1586 vhost_dev_stop(&n->dev);
1587 vhost_dev_reset_owner(dev: &n->dev, iotlb: umem);
1588 vhost_net_vq_reset(n);
1589done:
1590 mutex_unlock(lock: &n->dev.mutex);
1591 if (tx_sock)
1592 sockfd_put(tx_sock);
1593 if (rx_sock)
1594 sockfd_put(rx_sock);
1595 return err;
1596}
1597
1598static int vhost_net_set_features(struct vhost_net *n, u64 features)
1599{
1600 size_t vhost_hlen, sock_hlen, hdr_len;
1601 int i;
1602
1603 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1604 (1ULL << VIRTIO_F_VERSION_1))) ?
1605 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1606 sizeof(struct virtio_net_hdr);
1607 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1608 /* vhost provides vnet_hdr */
1609 vhost_hlen = hdr_len;
1610 sock_hlen = 0;
1611 } else {
1612 /* socket provides vnet_hdr */
1613 vhost_hlen = 0;
1614 sock_hlen = hdr_len;
1615 }
1616 mutex_lock(&n->dev.mutex);
1617 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1618 !vhost_log_access_ok(&n->dev))
1619 goto out_unlock;
1620
1621 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
1622 if (vhost_init_device_iotlb(d: &n->dev))
1623 goto out_unlock;
1624 }
1625
1626 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1627 mutex_lock(&n->vqs[i].vq.mutex);
1628 n->vqs[i].vq.acked_features = features;
1629 n->vqs[i].vhost_hlen = vhost_hlen;
1630 n->vqs[i].sock_hlen = sock_hlen;
1631 mutex_unlock(lock: &n->vqs[i].vq.mutex);
1632 }
1633 mutex_unlock(lock: &n->dev.mutex);
1634 return 0;
1635
1636out_unlock:
1637 mutex_unlock(lock: &n->dev.mutex);
1638 return -EFAULT;
1639}
1640
1641static long vhost_net_set_owner(struct vhost_net *n)
1642{
1643 int r;
1644
1645 mutex_lock(&n->dev.mutex);
1646 if (vhost_dev_has_owner(dev: &n->dev)) {
1647 r = -EBUSY;
1648 goto out;
1649 }
1650 r = vhost_net_set_ubuf_info(n);
1651 if (r)
1652 goto out;
1653 r = vhost_dev_set_owner(dev: &n->dev);
1654 if (r)
1655 vhost_net_clear_ubuf_info(n);
1656 vhost_net_flush(n);
1657out:
1658 mutex_unlock(lock: &n->dev.mutex);
1659 return r;
1660}
1661
1662static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1663 unsigned long arg)
1664{
1665 struct vhost_net *n = f->private_data;
1666 void __user *argp = (void __user *)arg;
1667 u64 __user *featurep = argp;
1668 struct vhost_vring_file backend;
1669 u64 features;
1670 int r;
1671
1672 switch (ioctl) {
1673 case VHOST_NET_SET_BACKEND:
1674 if (copy_from_user(to: &backend, from: argp, n: sizeof backend))
1675 return -EFAULT;
1676 return vhost_net_set_backend(n, index: backend.index, fd: backend.fd);
1677 case VHOST_GET_FEATURES:
1678 features = VHOST_NET_FEATURES;
1679 if (copy_to_user(to: featurep, from: &features, n: sizeof features))
1680 return -EFAULT;
1681 return 0;
1682 case VHOST_SET_FEATURES:
1683 if (copy_from_user(to: &features, from: featurep, n: sizeof features))
1684 return -EFAULT;
1685 if (features & ~VHOST_NET_FEATURES)
1686 return -EOPNOTSUPP;
1687 return vhost_net_set_features(n, features);
1688 case VHOST_GET_BACKEND_FEATURES:
1689 features = VHOST_NET_BACKEND_FEATURES;
1690 if (copy_to_user(to: featurep, from: &features, n: sizeof(features)))
1691 return -EFAULT;
1692 return 0;
1693 case VHOST_SET_BACKEND_FEATURES:
1694 if (copy_from_user(to: &features, from: featurep, n: sizeof(features)))
1695 return -EFAULT;
1696 if (features & ~VHOST_NET_BACKEND_FEATURES)
1697 return -EOPNOTSUPP;
1698 vhost_set_backend_features(dev: &n->dev, features);
1699 return 0;
1700 case VHOST_RESET_OWNER:
1701 return vhost_net_reset_owner(n);
1702 case VHOST_SET_OWNER:
1703 return vhost_net_set_owner(n);
1704 default:
1705 mutex_lock(&n->dev.mutex);
1706 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1707 if (r == -ENOIOCTLCMD)
1708 r = vhost_vring_ioctl(d: &n->dev, ioctl, argp);
1709 else
1710 vhost_net_flush(n);
1711 mutex_unlock(lock: &n->dev.mutex);
1712 return r;
1713 }
1714}
1715
1716static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1717{
1718 struct file *file = iocb->ki_filp;
1719 struct vhost_net *n = file->private_data;
1720 struct vhost_dev *dev = &n->dev;
1721 int noblock = file->f_flags & O_NONBLOCK;
1722
1723 return vhost_chr_read_iter(dev, to, noblock);
1724}
1725
1726static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1727 struct iov_iter *from)
1728{
1729 struct file *file = iocb->ki_filp;
1730 struct vhost_net *n = file->private_data;
1731 struct vhost_dev *dev = &n->dev;
1732
1733 return vhost_chr_write_iter(dev, from);
1734}
1735
1736static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1737{
1738 struct vhost_net *n = file->private_data;
1739 struct vhost_dev *dev = &n->dev;
1740
1741 return vhost_chr_poll(file, dev, wait);
1742}
1743
1744static const struct file_operations vhost_net_fops = {
1745 .owner = THIS_MODULE,
1746 .release = vhost_net_release,
1747 .read_iter = vhost_net_chr_read_iter,
1748 .write_iter = vhost_net_chr_write_iter,
1749 .poll = vhost_net_chr_poll,
1750 .unlocked_ioctl = vhost_net_ioctl,
1751 .compat_ioctl = compat_ptr_ioctl,
1752 .open = vhost_net_open,
1753 .llseek = noop_llseek,
1754};
1755
1756static struct miscdevice vhost_net_misc = {
1757 .minor = VHOST_NET_MINOR,
1758 .name = "vhost-net",
1759 .fops = &vhost_net_fops,
1760};
1761
1762static int __init vhost_net_init(void)
1763{
1764 if (experimental_zcopytx)
1765 vhost_net_enable_zcopy(vq: VHOST_NET_VQ_TX);
1766 return misc_register(misc: &vhost_net_misc);
1767}
1768module_init(vhost_net_init);
1769
1770static void __exit vhost_net_exit(void)
1771{
1772 misc_deregister(misc: &vhost_net_misc);
1773}
1774module_exit(vhost_net_exit);
1775
1776MODULE_VERSION("0.0.1");
1777MODULE_LICENSE("GPL v2");
1778MODULE_AUTHOR("Michael S. Tsirkin");
1779MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1780MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1781MODULE_ALIAS("devname:vhost-net");
1782

source code of linux/drivers/vhost/net.c